Engines provide a generally effective method of converting chemical energy into mechanical energy; they may turn fossil fuels into power that can drive the wheels of an automobile or the propeller of a boat. There are two general types of engines: piston engines and turbine engines. Piston engines are very common and have been adapted to numerous tasks. They provide relatively high amounts of torque or drive power, while being of a medium weight. Piston engines have numerous drawbacks including having many moving parts, having poor fuel efficiency, and being the root cause of significant amounts of pollution, while also being costly to assemble. Piston engines utilize a to-and-fro motion of the piston to generate torque. Consequently, piston engines are termed eccentric. Their eccentric nature is the cause of many of their inefficiencies.
Turbine engines are also common, particularly in aircraft. Known turbine engines operate by forcing a fluid (gas or liquid) through the engine, thus turning the fan-blades of the turbine. Known turbines may be characterized as momentum turbines because they operate by transferring the momentum of the fluid to the fan blades of the turbine. The hallmark of a momentum turbine is that if the rotation of the fan blades is prevented, the flowing fluid will continue to flow through the engine around the fan blades. Essentially no back pressure is created through the engine.
Known turbine engines have desirably high power to weight ratios, but have poor fuel efficiency, are difficult to cool and have short operational life spans given the extreme operating conditions. Also, turbine engines are generally unsuitable for use in ground vehicles because of the complex transmission required to translate the high speed of the turbine into the low speed of the vehicle wheels. Because turbine engines utilize pure rotary motion of the fan blades to generate torque, turbine engines are termed non-eccentric engines.
A Wankel engine combines some of the advantages of piston engines and turbine engines but sacrifices fuel efficiency and torque, which are both quite poor. Wankel engines use a single rotor and an eccentric shaft that wobbles the rotor.
Known compressors/pumps include gear pumps and lobe pumps. Although they utilize rotors and rotary motion, these types of compressors/pumps have several drawbacks. Effectively, gear/lobe pumps accomplish pumping by drawing fluid from one reservoir and transporting it to another reservoir. They may be characterized as one-way transporting valves. At no point do the rotors cooperate to compress or pump the fluid. In addition, they are inefficient and have relatively poor rates of pumping/compression. Also, gear and lobe pumps cannot be adapted for use as an engine. An example of a non-eccentric pump is in development by Star Rotor Corporation (College Station, Tex.).
Although non-eccentric, rotary engines may be known, such engines require extra seals in addition to the rotors to provide effective compression of the air/fuel mixture before combustion and effective transference of power from the combustion products. To achieve effective compression through the use of only the rotors, the rotors need to be constructed to tolerances on the order of a few ten-thousandths of an inch. Known techniques for designing the rotors (e.g. scribing as found in U.S. Pat. No. 2,920,610) cannot provide the necessary tolerances. Indeed, to this point tolerances of a few hundredths of an inch were all that was possible. Such tolerances will not provide sealing between the rotors. Moreover, rotors constructed to tolerances of a few hundredths of an inch have a high risk of being misshapen to a degree that the rotor will collide with each other during rotation, which is unacceptable.
The inventor provides a method for designing and constructing rotors having the necessary tolerance to provide sealing, but avoiding collision of the rotors during rotation.